EEC Tank/Charcoal Canister Question

[1970GMC350]

Hello all! My 1970 GMC has an EEC tank in it (it was built in California and sold in Oregon). What kind of vent lines is it supposed to have? I also assume my charcoal canister was removed as I can't find it. Does that have anything to do with venting and, if it does, is it possible to buy a replacement one? I can only find one line running from the gas tank to the fuel pump.

I spent last weekend trying to get my Quadrajet set correctly and also replaced the gas cap with a vented one I picked up from O'Reilly's. I immediately had, what I assume, was fuel pressure problems (bubbles in fuel filter, wouldn't idle correctly, etc.) I was thinking it was carburetor problems, messed with the mixture screws and ended up with a huge mess on my hands.